Currently, when satellites are placed in orbit around the Earth, they require a phase for the deployment of the structural elements carrying solar generators or antennas depending on the mission. This phase is particularly critical because the success of the mission depends on it.
The structural elements assembly is a structure which forms an articulated arm. Notably, amongst these structural elements there are yokes and/or solar panels and/or antennas. These elements are joined together by articulations from the root section to the end of the articulated arm.
In order to obtain a fully deployed posture of the structural elements and to minimize on the one hand the distribution of the motive force on the structural elements and on the other hand the kinematic interferences between the elements, it is often necessary to use a coupling system making it possible to coordinate and articulate the deployment of the structural elements in a uniform manner.
The initially-folded structure is deployed according to a movement sequence and at a determined speed. All the angles between two consecutive structural elements are opened according to a determined law by the coupling mechanism.
A known coupling system uses pulleys positioned on each of the articulations and cables connecting the pulleys making it possible to transfer the forces between the structural elements at the time of deployment.
In order to activate the first articulation which comprises a first pulley, a motor is usually situated at the root section, that is to say at the first articulation which joins together the payload of the satellite and the first structural element.
At the time of deployment, certain structures have, in addition to the coupling system, a system for locking the articulations together. The locking system makes it possible to immobilize the articulations and hence the couplings linked to the articulations for the rest of the mission of the satellite which will no longer need to deploy or retract these structural elements. The locking makes it possible to pass from a first life phase of the satellite corresponding to placement in orbit and deployment of its structural elements to a second life phase corresponding to the mission itself, in which the structural elements will have a specific mobility.
Once the structure is deployed, it may be necessary, throughout the lifetime of the satellite, to aim the structural elements at a target. In this second life phase, the deployment of the structure being completed, it is necessary, depending on the mission, to aim the structure in a direction of a target. For example, this may be the sun, if the structure comprises solar generators such as solar panels, or else a geographic region on the planet in the case of an antenna or else a precise point in space as required.
In order to protect the deployment phase, it is usually separated from the phase corresponding to the mission. Currently, the drive means used in each life phase are partitioned for security reasons. Notably, the motor which is used to articulate the structural elements for aiming at a target is different from the motor which is used to deploy the structure. The drive means are different depending on the life phase because the mechanisms of articulations with and without coupling of the two phases are different.
Usually, the pivoting connection of the root section is fixed after the deployment; it is said to be locked. In the prior art, there is at the root section of the payload, a pivoting connection making it possible to orient the whole of the deployed structure, the structure comprising all the attached structural elements when they are locked together.
One drawback of the solutions of the prior art is the space requirement and the weight of a second motor for aiming the deployed structure at a target.
A second drawback is that the locking system immobilizes the coupling of the articulations and locks the structure, the pulley mechanism making it possible to deploy the structural elements then no longer being used. The second motor then activates the articulations of the structure in order to cause all or some of it to pivot. This solution means that it is necessary to couple the locked coupling system with another system making it possible to rotate a portion of the structure so as to make it pivot towards a target.
One object of the invention is to alleviate the aforementioned drawbacks.